88 lines
3.6 KiB
Erlang
88 lines
3.6 KiB
Erlang
% RFC 4165 MTP2 P2P Adaption Layer coding / decoding
|
|
|
|
% (C) 2012 by Harald Welte <laforge@gnumonks.org>
|
|
%
|
|
% All Rights Reserved
|
|
%
|
|
% This program is free software; you can redistribute it and/or modify
|
|
% it under the terms of the GNU Affero General Public License as
|
|
% published by the Free Software Foundation; either version 3 of the
|
|
% License, or (at your option) any later version.
|
|
%
|
|
% This program is distributed in the hope that it will be useful,
|
|
% but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
% GNU General Public License for more details.
|
|
%
|
|
% You should have received a copy of the GNU Affero General Public License
|
|
% along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
%
|
|
% Additional Permission under GNU AGPL version 3 section 7:
|
|
%
|
|
% If you modify this Program, or any covered work, by linking or
|
|
% combining it with runtime libraries of Erlang/OTP as released by
|
|
% Ericsson on http://www.erlang.org (or a modified version of these
|
|
% libraries), containing parts covered by the terms of the Erlang Public
|
|
% License (http://www.erlang.org/EPLICENSE), the licensors of this
|
|
% Program grant you additional permission to convey the resulting work
|
|
% without the need to license the runtime libraries of Erlang/OTP under
|
|
% the GNU Affero General Public License. Corresponding Source for a
|
|
% non-source form of such a combination shall include the source code
|
|
% for the parts of the runtime libraries of Erlang/OTP used as well as
|
|
% that of the covered work.
|
|
|
|
-module(m2pa_codec).
|
|
-author('Harald Welte <laforge@gnumonks.org>').
|
|
-include("m2pa.hrl").
|
|
-include("mtp3.hrl").
|
|
|
|
-export([parse_msg/1, encode_msg/1]).
|
|
|
|
-compile({parse_transform, exprecs}).
|
|
-export_records([m2pa_msg]).
|
|
|
|
parse_m2pa_msgt(?M2PA_CLASS_M2PA, ?M2PA_TYPE_LINK, Len, Remain) ->
|
|
<<State:32/big, Filler/binary>> = Remain,
|
|
Ret = [{link_state, State}],
|
|
if
|
|
byte_size(Filler) > 0 ->
|
|
{undefined, [{filler, Filler}|Ret]};
|
|
true ->
|
|
{undefined, Ret}
|
|
end;
|
|
parse_m2pa_msgt(?M2PA_CLASS_M2PA, ?M2PA_TYPE_USER, 16, <<>>) ->
|
|
{undefined, []};
|
|
parse_m2pa_msgt(?M2PA_CLASS_M2PA, ?M2PA_TYPE_USER, Len, RemainIn) ->
|
|
<<Pri:1, _:7, Mtp3Bin/binary>> = RemainIn,
|
|
Mtp3 = mtp3_codec:parse_mtp3_msg(Mtp3Bin),
|
|
{Mtp3, []}.
|
|
|
|
parse_msg(DataBin) when is_binary(DataBin) ->
|
|
<<1:8, 0:8, MsgClass:8, MsgType:8, MsgLen:32/big, AllRemain/binary>> = DataBin,
|
|
<<_:8, BSN:24/big, _:8, FSN:24/big, Remain/binary>> = AllRemain,
|
|
{Mtp3, Params} = parse_m2pa_msgt(MsgClass, MsgType, MsgLen, Remain),
|
|
{ok, #m2pa_msg{msg_class = MsgClass, msg_type = MsgType,
|
|
fwd_seq_nr = FSN, back_seq_nr = BSN,
|
|
mtp3 = Mtp3, parameters = Params}}.
|
|
|
|
encode_m2pa_msgt(?M2PA_CLASS_M2PA, ?M2PA_TYPE_USER, undefined, _Params) ->
|
|
<<>>;
|
|
encode_m2pa_msgt(?M2PA_CLASS_M2PA, ?M2PA_TYPE_USER, Mtp3, _Params) when is_binary(Mtp3) ->
|
|
<<0:1, 0:7, Mtp3/binary>>;
|
|
encode_m2pa_msgt(?M2PA_CLASS_M2PA, ?M2PA_TYPE_USER, Mtp3, Params) when is_record(Mtp3, mtp3_msg) ->
|
|
Mtp3bin = mtp3_codec:encode_mtp3_msg(Mtp3),
|
|
encode_m2pa_msgt(?M2PA_CLASS_M2PA, ?M2PA_TYPE_USER, Mtp3bin, Params);
|
|
encode_m2pa_msgt(?M2PA_CLASS_M2PA, ?M2PA_TYPE_LINK, _, Params) ->
|
|
State = proplists:get_value(link_state, Params),
|
|
% FIXME: filler
|
|
Filler = <<>>,
|
|
<<State:32/big, Filler/binary>>.
|
|
|
|
|
|
encode_msg(Msg) when is_record(Msg, m2pa_msg) ->
|
|
#m2pa_msg{msg_class = MsgClass, msg_type = MsgType, fwd_seq_nr = FSN,
|
|
back_seq_nr = BSN, mtp3 = Mtp3, parameters = Params} = Msg,
|
|
Payload = encode_m2pa_msgt(MsgClass, MsgType, Mtp3, Params),
|
|
MsgLen = byte_size(Payload) + 16,
|
|
<<1:8, 0:8, MsgClass:8, MsgType:8, MsgLen:32/big, 0:8, BSN:24/big, 0:8, FSN:24/big, Payload/binary>>.
|